1. Field of the Invention
The present invention relates to an improvement of a variable compression ratio device of an internal combustion engine, comprising: a piston including a piston inner part connected to a connecting rod via a piston pin, and a piston outer part which is fitted on an outer periphery of the piston inner part so as to be only slidable in an axial direction and which is movable between a low compression ratio position near the piston inner part and a high compression ratio position near a combustion chamber, with an outer end surface of the piston outer part facing the combustion chamber, the piston inner part being provided with a piston outer part holding device that selectively holds the piston outer part in the low compression ratio position and the high compression ratio position.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2004-44512 discloses a variable compression ratio device of an internal combustion engine.